Systems, devices, and methods for combined wafer and photomask inspection

ABSTRACT

Systems, devices, and methods for combined wafer and photomask inspection are provided. In some embodiments, chucks are provided, the chucks comprising: a removable insert, wherein the removable insert is configured to support a wafer so that an examination surface of the wafer lies within a focal range when the chuck is in a first configuration, wherein the removable insert is inserted into the chuck in the first configuration; and a first structure forming a recess that has a depth sufficient to support a photomask so that an examination surface of the photomask lies within the focal range when the chuck is in a second configuration, wherein the removable insert is not inserted into the chuck in the second configuration.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.15/899,456 filed Feb. 20, 2018, which is hereby incorporated byreference herein in its entirety.

TECHNICAL FIELD

The present disclosure relates to mechanisms for combined inspection ofwafers and wafer photomasks.

BACKGROUND

Inspecting wafers and photomasks (collectively, specimens) for defectsand other characteristics is important for managing the semiconductormanufacturing process. Since the overall semiconductor manufacturingprocess involves hundreds of steps, it is critical to detect defects onthe wafer or photomask early in the manufacturing process. To helpdetect defects that occur during the manufacturing process (as well asother specimen characteristics), manufacturers often employ automaticmicroscopic inspection systems.

Current microscopic inspection systems used by manufacturers arededicated to either analyzing wafers for defects or analyzing photomasksfor defects. Since wafers and photomasks have different dimensions andproperties, separate microscopic inspection systems are used toaccommodate these different dimensions and properties. For example, astage included in an inspection system has a chuck attached to it thatis specifically sized to hold either a wafer or photomask. Since aphotomask is thicker than a wafer, existing chucks cannot be used forboth photomasks and wafers. Unfortunately, buying and maintainingseparate microscopic inspection systems can be very costly.

In a current wafer inspection system, in order to inspect both a waferand a photomask using the same system, at the very least, a chuck thatholds a specimen (e.g., a wafer or a photomask) to be examined wouldhave to be changed each time a different type of specimen was placed onthe chuck (e.g., switching from a wafer to a photomask or from aphotomask to a wafer). Manually changing chucks between wafer andphotomask inspections is disadvantageous, because additional adjustments(e.g., refocusing the objectives, reattaching vacuum connections,aligning automatic systems, and providing suitable safety features) areusually required when changing chucks. In particular, constantlyswitching between chucks can damage components of the inspection system(including the chuck itself), reduce the accuracy of specimen analyses,and introduce environmental contaminants into the inspection system.Also, changing out a chuck typically requires particularized knowledge,which operators of a microscopic inspection system may not have.Reducing the adjustments and calibrations that are necessary whenswitching between a wafer and photomask would reduce damage to themicroscopic inspection system, minimize error, and allow for arepeatable, quality controlled microscopic inspection system.

Accordingly, it is desirable to provide a new mechanism for the combinedinspection of wafers and photomasks.

SUMMARY

Systems, devices, and methods for combined wafer and photomaskinspection are provided. In some embodiments, chucks are provided, thechucks comprising: a removable insert, wherein the removable insert isconfigured to support a wafer so that an examination surface of thewafer lies within a focal range when the chuck is in a firstconfiguration, wherein the removable insert is inserted into the chuckin the first configuration; and a first structure forming a recess thathas a depth sufficient to support a photomask so that an examinationsurface of the photomask lies within the focal range when the chuck isin a second configuration, wherein the removable insert is not insertedinto the chuck in the second configuration.

In some embodiments, automatic inspection systems are provided, thesystems comprising: an end effector that is coupled to a robotic system;a microscopic inspection station; a controller that controls one or morecomponents of the automatic inspection system; and a chuck coupled to astage comprising: a removable insert, wherein the removable insert isconfigured to support a wafer so that an examination surface of thewafer lies within a focal range when the chuck is in a firstconfiguration, wherein the removable insert is inserted into the chuckin the first configuration; and a first structure forming a recess thathas a depth sufficient to support a photomask so that an examinationsurface of the photomask lies within the focal range when the chuck isin a second configuration, wherein the removable insert is not insertedinto the chuck in the second configuration.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A shows a front perspective view of an example of an inspectionsystem in accordance with some embodiments of the disclosed subjectmatter.

FIG. 1B shows a side view of an example of an inspection system inaccordance with some embodiments of the disclosed subject matter.

FIG. 2A shows a top perspective view of an example of a chuck inaccordance with some embodiments of the disclosed subject matter.

FIG. 2B shows a bottom perspective view of an example of a chuck inaccordance with some embodiments of the disclosed subject matter.

FIG. 3A shows a top view of an example of a chuck in accordance withsome embodiments of the disclosed subject matter.

FIG. 3B shows a top perspective view of an example of a chuck inaccordance with some embodiments of the disclosed subject matter.

FIG. 4A shows a top perspective view of an example of a chuck holding aphotomask in accordance with some embodiments of the disclosed subjectmatter.

FIG. 4B shows a top perspective view of an example of a chuck with aphotomask about to be placed in it in accordance with some embodimentsof the disclosed subject matter.

FIG. 5 shows a flow chart of an example of a process for loading a waferwithin an inspection system, such as the system illustrated in FIGS. 1Aand 1B, in accordance with some embodiments of the disclosed subjectmatter.

FIG. 6 shows a flow chart of an example of a process for loading aphotomask within an inspection system, such as the system illustrated inFIGS. 1A and 1B, in accordance with some embodiments of the disclosedsubject matter.

FIG. 7 shows a flow chart of an example of a process for applyinginterlock logic rules of an inspection system, such as the systemillustrated in FIGS. 1A and 1B, in accordance with some embodiments ofthe disclosed subject matter.

FIG. 8A shows an example illustration of a chuck with an insert insertedand a wafer resting on the chuck and the insert, and height profile ofeach, in accordance with some embodiments of the disclosed subjectmatter.

FIG. 8B shows an example illustration of a chuck without an insertinserted and a photomask sitting in a recess in the chuck, and heightprofile of each, in accordance with some embodiments of the disclosedsubject matter.

FIG. 9 shows a top perspective view of an example of a chuck and aninsert showing vacuum channels within the chuck and the insert inaccordance with some embodiments of the disclosed subject matter.

DETAILED DESCRIPTION

In accordance with some embodiments of the disclosed subject matter,mechanisms (which can include systems, methods, devices, apparatuses,etc.) for automated microscopic inspection of wafers and photomasks areprovided. Microscopic inspection (sometimes referred to as examination)refers to scanning, imaging, analyzing, measuring and any other suitablereview of a specimen using a microscope.

In some embodiments, microscopic inspection can be used with a single orseveral wafer material types including opaque, transparent orsemi-transparent. Further, in some embodiments, microscopic inspectioncan be configured to analyze one or all of substrate, epi, patterned anddiced wafers, or individual devices (on the wafer).

Although the following description refers to 300 mm wafers and 150 mmphotomasks, in some embodiments, the mechanisms described herein can beused to inspect any sized wafer and/or any sized photomask.

According to some embodiments of the disclosed subject matter,microscopic inspection can operate in two modes: a first mode forinspecting a wafer; and a second mode for inspecting a photomask. Asdescribed herein, in some embodiments, microscopic inspection can beconfigured to operate in a first mode for inspecting a wafer when aremovable wafer insert is inserted into a chuck and to operate in asecond mode for inspecting a photomask when the removable wafer insertis removed from the chuck.

FIGS. 1A (front perspective view) and 1B (side view) illustrate anexample inspection system 100 according to some embodiments of thedisclosed subject matter. At a high level, the basic components ofinspection system 100, according to some embodiments, include anautomated microscopic examination station 110, a pre-aligner 130, arobotic wafer handling system 140, a load port apparatus 160, andelectronics comprising hardware, software, and/or firmware.

In some embodiments, many of the components of inspection system 100, asshown in FIGS. 1A and 1B, can be enclosed within a cabinet housing madefrom aluminum, steel, plastic, glass, and/or any other suitable materialfor providing a micro clean environment within the cabinet housing. Thecabinet housing can include one or more access doors that provide accessto the internal components of inspection system 100. Further, in someembodiments, an air filtration system 125 for providing a micro cleanenvironment within the cabinet can be placed, for example at the top ofthe cabinet housing. The cabinet housing can include one or more storageregions, located for example at the bottom of the cabinet housing, forhousing a robotic wafer handling system and/or a vacuum source. Thecabinet housing can also include one or more platforms for mounting thevarious components of inspection system 100. In some embodiments,inspection system 100 can also be partially or completely open. In someembodiments, a variety of cabinet housing configurations can be used inaccordance with some embodiments of the disclosed subject matter.

As shown in FIGS. 1A and 1B, inspection system 100 includes an automatedmicroscopic examination station 110. In some embodiments, automatedmicroscopic examination station 110 comprises oculars, such as an ocularand/or a camera, a light source, an illuminator, one or more objectivelenses, a stage 115 and a chuck 200 coupled to the stage 115.

Automated microscopic examination station 110 can use any suitable typeof microscope. For example, in some embodiments, the microscope can bean optical microscope, an electron microscope, a scanning probemicroscope or any other suitable microscope. More particularly,automated microscopic examination station 110 can be implemented usingthe nSpec® optical microscope available from Nanotronics Imaging, Inc.of Cuyahoga Falls, Ohio Microscopic examination station 110 can beconfigured to inspect a specimen (e.g., a wafer or a photomask) andautomatically report on selected characteristics of the specimen.

According to some embodiments, automated microscopic examination station110 can include, one or more objectives. The objectives can havedifferent magnification powers and/or be configured to operate withbrightfield/darkfield microscopy, atomic force microscopy (AFM),differential interference contrast (DIC) microscopy, and/or any othersuitable form of microscopy. The objective and/or microscopy techniqueused to inspect a specimen can be controlled by software, hardware,and/or firmware in some embodiments. In some embodiments, any suitablesettings and/or adjustments to the components of automated microscopicexamination station 110 can be controlled by software, hardware and/orfirmware.

In some embodiments, an XY translation stage can be used for stage 115.The XY translation stage can be driven by stepper, servo, linear motor,and/or any other suitable mechanism.

In some embodiments, as shown in FIG. 1A, stage 115 and chuck 200 ofautomated microscopic examination station 110 can be mounted toisolation platform 135 located above a base platform 157 of the cabinethousing. For example, isolation platform 135 can be secured to thebottom frame of the cabinet housing. More particularly, in someembodiments, isolation platform 135, can be bolted into air pads 145, orany other suitable isolation mechanisms for fastening isolation platform135 to the bottom frame of the cabinet housing. Air pads 145 can helpreduce vibration (e.g., from fans of other components in inspectionsystem 100) to a specimen on chuck 200 during examination.

In some embodiments, an extended arm 148 can be mounted to isolationplatform 135. A motorized Z-column 147 coupled to the optics portion ofthe microscopic examination station 110 can be mounted to extended arm148. In some embodiments, the optics portion can be configured to moveup and down on motorized Z-column 147. Mounting the entire microscopicexamination station 110 to isolation platform above the base platform ofthe cabinet housing can help to distribute the weight of the microscopicexamination station 110 evenly and minimize vibration to the microscopicexamination station 110 during examination.

Pre-aligner 130 can be a stand-alone unit or integrated into the robotwafer handling system. In some embodiments, as shown in FIG. 1A,pre-aligner 130 is a stand-alone unit that is mounted with bolts orother suitable fasteners to a base platform of the cabinet. Pre-aligner130 can be used for orienting and/or centering a wafer or other suitablespecimen so that the specimen is properly oriented and centered when itis placed on chuck 200 for examination. In some embodiments, pre-aligner130 can use an indicator, for example a notch (e.g., on wafers 200 MM orgreater) or a flat (e.g., on wafers less than 200 MM) to orient thewafer so that the wafer is placed on the stage with a specificorientation. Pre-aligner 130 can rotate the wafer up to 360 degrees tofind the indicator. In some embodiments, pre-aligner 130 can measurecenter location and orientation of a wafer in a single rotation.

According to some embodiments, when a specimen is received bypre-aligner 130, pre-aligner 130 can be configured to turn on a vacuumto hold the specimen in place during the centering and/or aligningprocess. The pre-aligner can also be configured to start the alignmentand/or centering process only after the vacuum is turned on. When thepre-aligner has completed handling the wafer, the pre-aligner vacuum canbe configured to shut off.

Note that, in some embodiments, any suitable pre-aligner can be usedwith inspection system 100.

Pre-aligner 130 can be configured to support wafers of any suitable size(e.g., 50 mm to 300 mm, and/or any other suitable size). In someembodiments, pre-aligner 130 can also be configured to communicate withthe other components of inspection system 100. In some embodiments,communications and operations of pre-aligner 130 can be controlled bysoftware, hardware and/or firmware.

In some embodiments, a robotic wafer handling system for transferring awafer or other suitable specimen within inspection system 100 caninclude a base housing, a motor (not shown), a multi-axis extendable arm140, and an end effector 150. As shown in FIG. 1A, the base of therobotic wafer handling system can be stored in a region 155 below a baseplatform 157 of the cabinet housing. Multi-axis extendable arm 140 canextend above base platform 157 and can have two ends. One end can becoupled to the base of the robotic wafer handling system and the otherend can be coupled to end effector 150. In some embodiments, endeffector 150, as shown in FIG. 1A, can be in the shape of amulti-fingered hand. Different types of end effectors can be used withthe robotic wafer handling system in some embodiments. For example, insome embodiments, a vacuum end effector can be used that applies vacuumpressure to hold a specimen in place on the end effector. As anotherexample, in some embodiments, an edge grip end-effector can be used thatthat uses any suitable gripping mechanism to hold the specimen in placeon the end effector.

Note that, in some embodiments, multiple end effectors or a dual endeffector can be used with inspection system 100 to handle two or morespecimens at different locations within inspection system 100.

Note that, in some embodiments, any suitable robotic wafer handlingsystem(s) that includes any suitable multi-axis extendable arm and/orend effector can be used with inspection system 100. In someembodiments, end effector 150 of the robotic wafer handling system canbe configured to support any suitable size wafers, such as, for example,50 mm to 300 mm size wafers. In some embodiments, end effector 150 canbe configured to support a photomask. In some embodiments, all settings,communications, and operations of the robotic wafer handling system canbe controlled by software, hardware and/or firmware.

In some embodiments, a motor housed in the base of the robotic waferhandling system can control the movement of multi-axis extendable arm140 and end effector 150. For example, the motor can drive and controlmulti-axis extendable arm 140 and end effector 150 to select a waferfrom a cassette storage and move the wafer to different locations withininspection system 100. In some embodiments, end effector 150 cantransfer the wafer from the cassette storage to pre-aligner 130 foralignment, from pre-aligner 130 to chuck 200 for examination, and fromchuck 200 back to the cassette storage when examination of the wafer iscomplete.

In some embodiments, inspection system 100 can include a load portapparatus 160 (as shown in FIGS. 1A and 1B) for transferring wafersand/or other suitable specimens between a storage container andinspection system 100. In some embodiments, load port apparatus 160 canbe mounted to the outside of the cabinet housing of inspection system100. Load port apparatus 160 can include a door 180 that provides accessto the inside of inspection system 100. In some embodiments, the doorcan be configured to slide up and down to provide access to the insideof inspection system 100. Load port apparatus 160 also includes aplatform 175 for holding a wafer carrier or other suitable specimencarrier.

In some embodiments, a front opening unified pod (FOUP) 170 can beplaced on platform 175 of load port apparatus 160. FOUP 170 can includevarious coupling plates, pins and holes for securing the FOUP to theload port platform. In some embodiments, FOUP 170 can be a plasticenclosure designed to cleanly and securely hold wafers and to allowwafers to be transferred from FOUP 170 to microscopic inspection system100 for processing. FOUP 170 can include a side door that can be openedto provide access to wafers inside. In some embodiments, for example,FOUP 170 can hold 25 wafers. In some embodiments, a side door of FOUP170 can be aligned with load port door 180 to create a seal. Load portapparatus 160 can be configured to draw the mated doors of load portapparatus 160 and FOUP 170 down and up. In one position (e.g., the downposition), the wafers in FOUP 170 can be exposed to the inside of theinspection system 100 and provide access to end effector 150 to select awafer. In a second position (e.g., the up position), both FOUP 170 andinspection system 100 are sealed off from each other, restricting accessbetween them. FOUP 170 can include sensors to detect and communicatewith inspection system 100 when wafers are present in FOUP 170.

In some embodiments, end effector 150 can include one or more sensorsfor mapping the inside of FOUP 170 to detect each location in FOUP 170that stores a wafer.

FIG. 1B, shows a side view of inspection system 100 and some of itscomponents, according to some embodiments of the disclosed subjectmatter. In particular, FIG. 1B shows an emergency power off (EPO) switch165 coupled to the outside of inspection system 100 that allows anoperator to electrically shut down all robotic operations of the roboticwafer handling system, as well as any other electrical operation ofinspection system 100, when the switch is activated. In someembodiments, the vacuum remains on to prevent damage to the specimen.

The cabinet housing of inspection system 100, can also include an accessdoor 178 that provides access to components within the inspectionsystem. Access door 178 is coupled to an interlock hinge 185, or anyother suitable switch, that is designed to disable any moving componentwithin inspection system 100 when access door 178 is open. In someembodiments, any access door to the inspection system 100 can include aswitching mechanism that is designed to disable any moving componentwithin inspection system 100 when the door is opened.

In some embodiments, the electronics controlling inspection system 100can be located in a separate compartment of the cabinet housing, forexample, below automated microscopic examination station 110. In somesuch embodiments, electronics controlling inspection system 100 can beaccessed using access door 168. In some embodiments, the electronics caninclude any suitable hardware, software, and/or firmware for controllingthe operation, communication, and settings of the components of theinspection system 100, as described herein. In some embodiments,inspection system 100 includes software and/or hardware to providemotion control, specimen handling, safety interlocks, and analysis ofwafers and photomasks. Hardware can include, for example, computers,microprocessors, microcontrollers one or more EPROMS, EEPROMs,application specific integrated circuits (ASICs) in addition to otherhardware elements. In some embodiments, individual components withininspection system 100 can include their own software, firmware, and/orhardware to control the individual components and communicate with othercomponents in inspection system 100.

Inspection system 100 can also include one or more display monitors 195coupled to the outside of inspection system 100. Display monitors 195can display images captured by microscopic examination station 110. Anadjustable swingarm 188 for placing input devices (e.g., a keyboard,mouse or joystick) for controlling the electronics can also be coupledto inspection system 100, and located, for example, below displaymonitors 195.

FIG. 2A (top view) and FIG. 2B (bottom view), show the generalconfiguration of an embodiment of a chuck 200 and a removable waferinsert 205 in accordance with some embodiments of the disclosed subjectmatter. Chuck 200 can be formed from aluminum, steel and/or any othersuitable material(s). Chuck 200 is designed to support both a photomaskand a wafer at different times. In some embodiments, chuck 200 isC-shaped with a relief area 330 (as shown in FIGS. 3A and 3B) designedto allow access to a two-fingered end effector 150 for placing orremoving a specimen on to or off of the chuck. Chuck 200 can be mountedto the top surface of stage 115 of microscopic examination station 110,using standard fasteners like spring screws or leveling screws.

In some embodiments, chuck 200 can include a removeable wafer insert 205designed to support a wafer and to allow the insert to be removed fromthe base of chuck 200. In some embodiments, chuck 200 can be in a firstconfiguration when removable wafer insert 205 is inserted in chuck 200,and, in the first configuration, chuck 200 can be used to support awafer for inspection by inspection system 100. In some embodiments,chuck 200 can be in a second configuration when removable wafer insert205 is not inserted in chuck 200, and, in the second configuration,chuck 200 can be used to support a photomask for inspection byinspection system 100.

Removable wafer insert 205 can include locating pins 210 (as shown inFIG. 2B) that engage holes 227 (as shown in FIG. 2A) that alignremovable wafer insert 205 to a corresponding mate 230 located within arecess of chuck 200. In some embodiments, corresponding mate 230 caninclude one or more vacuum cups 240. Vacuum cups 240 can be connected toa vacuum source (not shown) and designed to provide a vacuum interfaceto secure removable wafer insert 205 to chuck 200 when inspection system100 is used to inspect a wafer, and/or to secure a photomask (e.g.,photomask 405, as shown in and described below in connection with FIGS.4A and 4B) to chuck 200 when inspection system 100 is used to inspectphotomask. In some embodiments, the vacuum source will not turn on untilall the access doors to the cabinet of inspection system 100 are closed.Note that, in some embodiments, any other suitable fasteningmechanism(s) can be used to secure removable wafer insert 205 to chuck200.

Removable wafer insert 205 can also include an interlocking safetymechanism like an interlocking pin 215 (as shown in FIG. 2B).Interlocking pin 215 can activate a sensor 220, located on chuck 200,for sensing when removable wafer insert 205 is inserted into or removedfrom chuck 200. Sensor 220 can be any suitable sensor for detecting thepresence of pin 215, such as an optical sensor or an electro-mechanicalswitch. The output of sensor 220 can be connected to the electronics ofinspection system 100 via interlock sensor connector 325 (as shown inFIGS. 3A and 3B) and can be configured to enable certain electricaloperations (e.g., the electrical operations of the robotic waferhandling system) when removable wafer insert 205 is inserted into chuck200 and to disable certain electrical operations (e.g., the electricaloperations of the robotic wafer handling system) when removable waferinsert 205 is removed from chuck 200.

The thickness of removable wafer insert 205, in some embodiments, can bethick enough to cause the top surface of insert 205 to be at the samelevel and flat with respect to outer wafer support surface 206. FIG. 8Ashows a simple cross-sectional illustration of a chuck 200, a removableinsert 205, and a wafer 805. As illustrated, the top of insert 205 canbe flat and level with outer wafer support surface 206 so that a wafer805 can lie flat across insert 205 and surface 206.

FIG. 8B shows a simple cross-sectional illustration of a chuck 200 and aphotomask 405. As illustrated, the top of photomask 405 can be at thesame level and flat with respect to outer wafer support surface 206 insome embodiments. Thus, in such embodiments, the height (h₂) at the topof the photomask with respect to the bottom of the chuck can bedifferent than the height (h₁) at the top of a wafer when sitting onsurface 206 and insert 205 (as shown in FIG. 8A) by an amount equal tothe thickness of a wafer. For example, in some embodiments, h₁ and h₂can be different but both be within a focal range (which can be anysuitable thickness, such as 1 mm thick, in some embodiments) ofautomated microscopic examination station 110 (FIG. 1A).

In some embodiments, rather than being at the same level and flat withrespect to outer wafer support surface 206, the top of photomask 405 canbe slightly higher than outer wafer support surface 206 (e.g., by anamount around or equal to the thickness of a wafer) so that the height(h₂) at the top of the photomask with respect to the bottom of the chuckis substantially the same as the height (h₁) at the top of a wafer whensitting on surface 206 and insert 205 (as shown in FIG. 8A).

In some embodiments, removable wafer insert 205 and chuck 200 caninclude multiple vacuum channels (e.g., vacuum ring 305 and outer vacuumchannel 310 as shown in FIGS. 3A and 3B) for providing vacuum pressureat various locations on chuck 200 to hold a specimen firmly in placeduring examination. The vacuum configuration for chuck 200 can provideany suitable vacuum pressure for the type of specimen being examined.

As shown in FIGS. 3A and 3B, in some embodiments, vacuum ring 305 can belocated on removable wafer insert 205 and outer vacuum channel 310 canbe located in outer wafer support surface 206. The vacuum can besupplied via vacuum valves 315 and 316, which, in some embodiments, canbe located along the outer edge of chuck 200 so as not to interfere withthe vacuum supply when removable wafer insert 205 is removed from chuck200. Vacuum valves 315 and 316 can be coupled (e.g., via a hose) with avacuum source, which can be located in some embodiments withininspection system 100. In some embodiments, both vacuum valves 315 and316 can be open when a wafer is placed on chuck 200 and provide vacuumflow to both vacuum ring 305 and outer vacuum channel 310. In someembodiments, when a photomask, which can have a smaller surface areathan a wafer, is placed on chuck 200, then only vacuum valve 316 can beopened to provide sufficient vacuum support to vacuum cups 240 forproviding vacuum support to a photomask. For example, when photomask 405(as shown in FIGS. 4A and 4B) is placed on chuck 200, the vacuum supplyto outer vacuum channel 310 can remain turned off, because photomask 405does not extend to vacuum channel 310. In some embodiments, any suitablevacuum configurations can be used with chuck 200. In some embodiments,the source vacuum can be regulated to 60 KPa, which can be applied forboth wafers and photomasks.

FIG. 9 shows an illustration of an example of vacuum channels 902, 904,906, 908, and 910 for connecting valves 315 and 316 (FIGS. 3A and 3B) tovacuum ring 305, vacuum channel 310 and vacuum cups 240.

Chuck 200 can also include any suitable number of leveling screws 320Aand 320B (e.g., 3 point leveling screws, and/or any other suitablenumber and/or type of leveling screws) to enable an operator to ensurethat outer wafer support surface 206 of the chuck is level and flat.More particularly, one set of leveling screws 320A can be used to levelouter wafer support surface 206 with respect to the focal range (whichcan be any suitable thickness, such as 1 mm thick, in some embodiments)of automated microscopic examination station 110 (FIG. 1A) byrepositioning the chuck with respect to a lower structure to which it isattached. Another set of leveling screws 320B can be used to level andadjust the height of removable wafer insert 205 when it is inserted intochuck 200 by repositioning corresponding mate 230 with respect to theremainder of the chuck.

In some embodiments, chuck 200 can be designed to support wafers ofdifferent sizes and thicknesses by using wafer inserts of differentthicknesses. For example, a first removable wafer insert 205 can have afirst thickness (e.g., 151700 μm when used with a chuck having a recessthat is 152000 μm deep with respect to a point within the focal range ofautomated microscopic examination station 110) for a first waferthickness (e.g., 300 μm) and a second removable wafer insert 205 canhave a second thickness (e.g., 151840 μm when used with the chuck havinga recess that is 152000 μm deep with respect to the point within thefocal range of automated microscopic examination station 110) for asecond wafer thickness (e.g., 160 μm) so that the combined thickness(e.g., 152000 μm) of the insert and the wafer put the examinationsurface of the wafer within the focal range of automated microscopicexamination station 110 (FIG. 1A).

Other features, like the configuration of vacuum channels and theplacement of leveling screws, can be suitably designed based on the sizeof the wafers.

FIG. 4A (a top perspective view of example chuck 200 when photomask 405is on the chuck) and FIG. 4B (a top perspective view of example chuck200 before photomask 405 is placed on the chuck) show an illustration ofchuck 200 in which removable wafer insert 205 is removed to allow forphotomask 405 to be placed on chuck 200. As shown, chuck 200 can includefour corner shelves 415 that create a recess in the chuck (which can beat least as thick as the thickness of photomask 405 in some embodiments)for placing the surface of photomask 405 within the same microscopicinspection focal range (which can be any suitable thickness, such as 1mm, in some embodiments) as a wafer when the photomask is positioned onthe chuck, as described above in connection with FIGS. 8A and 8B. Chuck200 can also include first and second relief areas 410 for placing orremoving photomask 405 on to or off of chuck 200. In some embodiments,keeping the surface of a wafer and the surface of a photomask in thesame focal range (which can be any suitable thickness, such as 1 mm, insome embodiments) eliminates the need to change the focus of themicroscopic examination station 110 when switching between inspecting awafer and inspecting a photomask.

As shown in FIG. 4B, in some embodiments, vacuum cup 240 (as describedabove in connection with FIG. 2A) can provide a vacuum interface forphotomask 405 to hold the photomask firmly in place during inspection.FIG. 4B also shows corner shelves 415, which are also designed toprovide support to photomask 405.

FIG. 5, with further reference to FIGS. 1-4, shows at a high level, awafer loading operation 500 of inspection system 100, in accordance withsome embodiments of the disclosed subject matter. The wafer loadingprocess 500 can use inspection system 100.

At 510, FOUP 170 can be placed on load port apparatus 160, so that thedoor of FOUP 170 and load port door 180 fasten together in a sealablemanner. FOUP 170 and load port door 180 can be lowered together,exposing the wafers in FOUP 170 to the inside of inspection system 100and providing access to end effector 150 to select a wafer.

At 520, robotic end effector 150 can map the FOUP to determine how manywafers are in the FOUP and where they are located. In some embodiments,robotic end effector 150 can map the FOUP using any suitable sensorsassociated with robotic end effector 150. End effector 150 can then pickup a wafer from FOUP 170, and transfer the wafer to pre-aligner 130. Insome embodiments, a vacuum can be turned on when or after a wafer ispicked up for keeping the wafer on end effector 150 and the vacuum canbe turned off after the wafer is transferred to pre-aligner 130.

At 530, pre-aligner 130 can center and/or orient a wafer (e.g., by usinga notch or a flat). In some embodiment, pre-aligner 130 can turn on avacuum when or after it receives the wafer before it starts any wafercentering and/or aligning procedure, and turn off the vacuum when orafter the wafer centering and/or aligning procedure is completed.

At 540, end-effector 150 can pick up a wafer from pre-aligner 130 andplace the wafer on chuck 200 for inspection by automated microscopicexamination station 110. Vacuum pressure for chuck 200 can be turned onwhen or after the wafer is placed on chuck 200.

At 550, process 500 can perform microscopic inspection on the waferusing any suitable technique or combination of techniques. For example,as described above in connection with FIGS. 1A and 1B, process 500 canuse an automated microscopic examining station that includes anysuitable type of microscope (e.g., an optical microscope, an electronscanning microscope, a scanning probe microscope, and/or any othersuitable type of microscope) to obtain any suitable information duringinspection of the wafer.

At 560, when or after inspection of the wafer is completed, vacuumpressure can be turned off and end effector 150 can retrieve the waferfrom chuck 200 and return the wafer to FOUP 170.

In some embodiments, once all the wafers are inspected, load port door180 and FOUP 170 can be raised together, sealing off the access betweenFOUP 170 and inspection system 100. In some embodiments, vacuum pressurecan be applied when a wafer is present on end effector 150, and thevacuum for the end effector can be turned off when the wafer istransferred to another component of inspection system 100.

Note that, in some embodiments, wafers can be manually loaded intoinspection system 100 and placed directly on chuck 200 without usingFOUP 170.

Additionally, note that, in some embodiments, process 500 can beperformed in response to determining that removable wafer insert 205 (asshown in and described above in connection with FIGS. 2A and 2B) hasbeen inserted in chuck 200. For example, in some embodiments, process500 can be performed in response to determining that interlocking pin215 of removable wafer insert 205 has activated sensor 220 of chuck 200,as described above in connection with FIGS. 2A and 2B.

FIG. 6, with further reference to FIGS. 1-4, shows at a high level, aphotomask loading operation 600 of inspection system 100, in accordancewith some embodiments of the disclosed subject matter. Photomask loadingprocess 600 can use inspection system 100.

At 610, access door 178 can be opened (as shown in FIG. 2). This doorcan be opened in any suitable manner in some embodiments. For example,this door can be opened manually by an operator or automatically by anactuator in some embodiments.

At 620, in some embodiments, interlock hinge 185 can be activated inresponse to detecting that access door 178 has been opened. In some suchembodiments, process 600 can disable any moving component withininspection system 100, including disabling end effector 150.

At 630, removable wafer insert 205 (as shown in FIG. 2) can be removedand a photomask can be recessed into chuck 200. Insert 205 can beremoved in any suitable manner, such as manually by an operator or usingan automated mechanism. Photomask can be recessed into chuck 200 in anysuitable manner, such as manually by an operator or using an automatedmechanism.

At 640, microscopic examination station 110 can inspect the photomask.In some embodiments, microscopic examination station 110 can use anysuitable parameters and techniques for inspecting the photomask. Forexample, in some embodiments, microscopic examination station 110 canuse the same or a different focus and objective as was used to inspect awafer, as described above in connection with FIG. 5. As another example,in some embodiments, microscopic examination station 110 can use adifferent microscopic technique (e.g., using AFM microscopy) than atechnique used to inspect a wafer.

At 650, after inspection of the photomask, the photomask can be removedfrom chuck 200 and removable wafer insert 205 can be inserted into chuck200. Photomask can be removed from chuck 200 in any suitable manner,such as manually by an operator or using an automated mechanism. Insert205 can be inserted in any suitable manner, such as manually by anoperator or using an automated mechanism.

At 660, access door 178 can be closed when or after removable waferinsert 205 is inserted into chuck 200. Access door 178 can be closed inany suitable manner, such as manually by an operator or using anautomated mechanism.

At 670, the robotic wafer handling system of inspection system 100 canbe enabled, as described above in connection with FIG. 5.

Note that, in some embodiments, process 600 can be performed in responseto determining that removable wafer insert 205 (as shown in anddescribed above in connection with FIGS. 2A and 2B) is not inserted inchuck 200. For example, in some embodiments, process 600 can beperformed in response to determining that interlocking pin 215 ofremovable wafer insert 205 has not activated sensor 220, as describedabove in connection with FIGS. 2A and 2B.

Additionally, note that, in some embodiments a photomask can also beautomatically loaded into inspection system 100, similar to thetechniques used for automatically loading wafers into the inspectionsystem. For example, in some embodiments, a specially designed photomaskstorage container can be loaded onto load port apparatus 160. The frontcover of the photomask storage container and load port door 180 can belowered, exposing the photomasks inside the photomask storage containerto the inside of inspection system 100. The photomask storage containerand/or end effector 150 can be designed to sense the presence of aphotomask and communicate with the control system of inspection system100 to perform operations appropriate for photomask inspection. Thephotomask storage container can be designed to include a designated areafor storing removable wafer insert 205. Before any photomask is loadedinto inspection system 100, end effector 150 can be configured to removeremovable wafer insert 205 from chuck 200 and place it in a designatedarea in the photomask storage container. Once removable wafer insert 205has been removed, end effector 150 can select a photomask from thephotomask storage container and transfer it to chuck 200 for inspectionand/or imaging by microscopic examination station 110. After inspectionof the photomask, end effector 150 can pick up the photomask from chuck200 and return the photomask to the photomask storage container. Onceall the photomasks are inspected, end effector 150 can select removablewafer insert 205 and place it back on chuck 200.

FIG. 7, with further reference to FIGS. 1-4, shows at a high level anexample of logic rules 700 for interlocking safety features of aninspection system, such as inspection system 100, in accordance withsome embodiments of the disclosed subject matter.

As shown in FIG. 7, according to some embodiments, an inspection systemcan include three interlocking mechanisms for determining whether arobotic wafer handling system, such as the one shown in and describedabove in connection with FIG. 5, is to be deactivated or activated.

In some embodiments, the robotic wafer handling system can be disabledat 740 in response to determining that an emergency power off (EPO)button has been activated (at 710), that an access door to the enclosedinspection system 100 is not closed (at 720), or that a wafer insert isnot present in chuck 200 (at 730). Note that, in some embodiments, anyone of an activated EPO button, not closed access door, and/or lack ofremovable wafer insert in chuck 200 can disable all robotic operationsat 740 by the robotic wafer handling system and/or moveable componentswithin inspection system 100.

Conversely, in some embodiments, the robotic operations of the roboticwafer handling system can be enabled at 780 in response to determiningthat the following conditions have been met: the EPO button is notenabled (750), access door 178 to inspection system 100 is closed (760),and removable wafer insert 205 is inserted into chuck 200 (770).

The division of when the particular portions of processes 500, 600,and/or 700 are performed can vary, and no division or a differentdivision is within the scope of the subject matter disclosed herein.Note that, in some embodiments, blocks of processes 500, 600, and/or 700can be performed at any suitable times. It should be understood that atleast some of the portions of processes 500, 600, and/or 700 describedherein can be performed in any order or sequence not limited to theorder and sequence shown in and described in the FIGS. 5, 6, and 7 insome embodiments. Also, some of the portions of processes 500, 600,and/or 700 described herein can be or performed substantiallysimultaneously where appropriate or in parallel in some embodiments.Additionally or alternatively, some portions of processes 500, 600,and/or 700 can be omitted in some embodiments.

Any one or more of processes 500, 600, and/or 700 can be implemented inany suitable hardware and/or software, for example, one or more EPROMS,EEPROMs, a programmable logic device, application specific integratedcircuits (ASICs) or any other hardware or firmware elements.

The automated microscopic inspection system and method that integratesthe testing of wafers and photomasks in a single system have beendescribed in detail with specific reference to these illustratedembodiments. It will be apparent, however, that various modificationsand changes can be made within the spirit and scope of the disclosure asdescribed in the foregoing specification, and such modifications andchanges are to be considered equivalents and part of this disclosure.The scope of the invention is limited only by the claims that follow.

What is claimed is:
 1. A chuck, comprising: a body having an openingformed therethrough, the body comprising a first support surface and asecond support surface positioned below the first support surface, thesecond support surface configured to support a photomask when the chuckis in a first configuration; and a removable insert configured tointerface with the second support surface when the chuck is in a secondconfiguration, the removable insert having a thickness such that theremovable insert and the first support surface form a first integratedsupport surface configured to support a substrate.
 2. The chuck of claim1, further comprising: at least one vacuum channel formed in the body,the at least one vacuum channel configured to engage the substrate whenthe chuck is in the second configuration and engage the photomask whenthe chuck is in the first configuration.
 3. The chuck of claim 1,wherein the substrate lies within a focal range when the chuck is in thesecond configuration.
 4. An automatic inspection system, comprising: anend effector that is coupled to a robotic system; a microscopicinspection station; a controller that controls one or more components ofthe automatic inspection system; and a chuck coupled to a stage, thechuck comprising: a body having an opening formed therethrough, the bodycomprising a first support surface and a second support surfacepositioned below the first support surface, the second support surfaceconfigured to support a photomask when the chuck is in a firstconfiguration; and a removable insert configured to interface with thesecond support surface when the chuck is in a second configuration, theremovable insert having a thickness such that the removable insert andthe first support surface form a first integrated support surfaceconfigured to support a substrate.
 5. The automatic inspection system ofclaim 4, wherein the automatic inspection system is enclosed.
 6. Theautomatic inspection system of claim 4, wherein the end effector isconfigured to automatically load a substrate into the automaticinspection system.
 7. The automatic inspection system of claim 4,wherein the end effector is configured to automatically load thephotomask into the automatic inspection system.
 8. The automaticinspection system of claim 4, wherein operations associated with therobotic system are deactivated when the removable insert is not insertedinto the chuck.
 9. The automatic inspection system of claim 4, whereinoperations associated with the robotic system are deactivated when anaccess door of the automatic inspection system is open.
 10. Theautomatic inspection system of claim 4, wherein operations associatedwith the robotic system are deactivated when an emergency power offbutton of the robotic system has been activated.
 11. The automaticinspection system of claim 4, wherein the removable insert has one ormore locating pins that connect the removable insert to the chuck whenthe chuck is in the second configuration.
 12. The automatic inspectionsystem of claim 4, wherein the chuck further comprises: at least onesecond vacuum channel formed therein, the at least one second vacuumchannel configured to engage the substrate when the chuck is in thesecond configuration and engage the photomask when the chuck is in thefirst configuration.